I ordered four boxes of checks from this company.Boxes 1 and 4 arrived but not 2 and 3.

I am first told by the first agent that I was too ignorant to order "secure shipping", although not in those words. The next thing is that if "the other boxes of checks do not arrive in 15 business days" they will send me more checks. B F D. In the meantime what happens to my checking account balance should someone [mail people?] have my checks?